Branching ratio andCPasymmetry ofBs→π0η(′)decays in the perturbative QCD approach

Abstract

We calculate the branching ratios and $CP$-violating asymmetries for ${B}_{s}^{0}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{0}{\ensuremath{\eta}}^{(\ensuremath{'})}$ decays in the perturbative QCD (pQCD) factorization approach here. We not only calculate the usual factorizable contributions, but also evaluate the nonfactorizable and annihilation type contributions. The pQCD predictions for the $CP$-averaged branching ratios are $\mathrm{BR}({B}_{s}^{0}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{0}\ensuremath{\eta})\ensuremath{\approx}0.86\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}7}$ and $\mathrm{BR}({B}_{s}^{0}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{0}{\ensuremath{\eta}}^{\ensuremath{'}})\ensuremath{\approx}1.86\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}7}$. The pQCD predictions for the $CP$-violating asymmetries are ${A}_{CP}^{\mathrm{dir}}({\ensuremath{\pi}}^{0}\ensuremath{\eta})\ensuremath{\sim}\ensuremath{-}4.5%$, ${A}_{CP}^{\mathrm{dir}}({\ensuremath{\pi}}^{0}{\ensuremath{\eta}}^{\ensuremath{'}})\ensuremath{\sim}\ensuremath{-}9.1%$, ${A}_{CP}^{\mathrm{mix}}({\ensuremath{\pi}}^{0}\ensuremath{\eta})\ensuremath{\sim}\ensuremath{-}0.2%$, and ${A}_{CP}^{\mathrm{mix}}({\ensuremath{\pi}}^{0}{\ensuremath{\eta}}^{\ensuremath{'}})\ensuremath{\sim}27%$ but with large errors. The above pQCD predictions can be tested in the forthcoming LHC-b experiments at CERN.